We've all been there: You're at an event listening to a boring CEO and you keep checking your Blackberry, going over a mental to-do list, or just looking at your watch--anything to keep your mind occupied. You may have been excited about the speaker, having heard about her accomplishments or knowing her personally. But you leave thinking less of that CEO than you did when you walked in.

I've seen bad CEO presentations more times than I can count. I've also booked speakers for seminars and events, and I'm often surprised to find that a CEO who is engaging one-on-one is dull when speaking to a group.

CEOs have to be effective public speakers because they are the face of their companies and embody the brand itself. At the very least, they need to represent a polished, organized and energetic brand. However, it's a missed opportunity if they don't also use the pulpit to inspire, motivate and create an impression of corporate strength.

Every day I work as an executive communications coach, I see that effective public speaking is a learned skill. Tricks of the trade that anyone can grasp and incorporate will significantly improve a speaker's impact. Yet when CEOs accept speaking engagements, they often view them as an afterthought on their busy schedules.

So why do otherwise engaging, charismatic leaders bomb at public speaking? Here's what I've seen:

Winging it. This is by far the biggest reason for a boring speech. The presenter chooses not to prepare because of lack of time or interest, or even because he or she doesn't want to appear rehearsed (as if showing you care were a bad thing). Few great speakers can just show up without developing their thoughts and practicing. Of those who can, many have already told what seems like off-the-cuff anecdotes many times before. At the very least, every speaker should know the audience's and the organizer's expectations for the presentation before going through with it. Comments that you have practiced out loud should be prepared. Your introduction should also grab the audience's attention.

Wrong comments, wrong place. Often speakers fail to tailor their remarks to the audience in the room. This goes hand-in-hand with winging it--either the speaker didn't find out what was expected or knew and didn't bother to adapt the content due to time constraints. You can quickly bore an audience with generic comments that aren't relevant. People want to feel that you are speaking directly to them. On the other hand, an overly formal presentation can be equally off-putting if the tone of the event is conversational. Providing your speech with enough structure that you feel secure enough for a couple of informal comments, however, can help you look prepared and casual at the same time.

Can't get off the stump. It's common in politics to have a stump speech--a talk you give over and over again to different audiences. Unfortunately, many CEOs have their own stump speeches and don't know when to retire them. One CEO I've heard--who is actually a very engaging speaker--had this problem. The first time I saw him give the speech, it was inspiring. The second time, it was mildly entertaining. The third time I was annoyed. Business communities are small and audiences frequently overlap. Only give a talk once unless you are positive the audience is entirely new.

Not enough narrative. Most speeches at your average conference are filled with details and pontifications. They are quickly forgotten. Humans don't retain data points, but they love hearing stories and learning about the experiences of others. As a speaker, your stories are the most powerful and memorable thing you can share. By weaving personal experiences into a speech and talking from the heart, you draw the audience in.

Selling too hard. There's an unspoken contract between speakers and audiences: You are there to inform them, not to sell them. Audiences tune out quickly if they believe a speaker is using the podium to advertise his or her products or services. Yet many CEOs feel they can't pass up an opportunity to let so many people at once hear how great their company is. This is a huge mistake. As the CEO, you are the embodiment of the company. If you are an interesting, engaging speaker, that's all the selling you need.

Piling on panels. Many business speeches take the form of panels, where several speakers give their perspectives on the topic at hand. These are ripe for boring speeches because, with the shared air time, participants feel less pressure to prepare. In fact, to be an effective panelist you need to be extra interesting by compiling provocative and memorable comments ahead of time that set you apart from the other speakers. You also have to resist the urge to pile on--rewording what someone else has already said to show agreement--because it wastes your chance to make a powerful comment of your own. It's also painfully dull for the audience.

Here's the irony of all these boring CEO speeches: Leaders are usually interesting people who have the ability to connect with others. If they avoid common pitfalls, they can become compelling speakers and use the speaking opportunity to their advantage.